1. Field of the Invention
This invention relates to a washing machine having an automatic liquid level control, and more particularly to a washing machine wherein the correct amount of washing fluid is selected for the requirements of a given load of clothes, automatically and with no pre-selection by an operator.
2. Description of the Prior Art
Various means have been provided for automatically controlling the liquid level in a washing machine. U.S. Pat. No. 3,086,836 discloses an automatic liquid level control wherein a given volume of liquid is added to the clothes load, the volume not absorbed by the clothes load is measured, and that measurement is utilized to determine the additional volume of liquid to be added to obtain the proper total amount of liquid.
U.S. Pat. No. 3,498,090 utilizes a control system for use in an automatic washer to automatically control the quantity of liquid added to the machine's tub during the wash and rinse operations by using a torque signal generated in the machine by action of the agitator.
U.S. Pat. No. 3,478,374 provides for an automatic liquid level control in an automatic washing machine which involves employing a sensing zone in proximity to the axis of the agitator, applying a reduced pressure at the sensing zone, and then introducing additional amounts of liquid into the machine when the liquid has been depleted from the sensing zone as a result of an excessive amount of wash fabric being present in comparison to the amount of washing liquid.
U.S. Pat. No. 3,478,373 provides an automatic liquid level control which responds to the flow of liquid in a predetermined flow path to sense when the proper amount of washing fluid is present in the tub of the washer.